Branch tree LaTeX

Question

I need to make a branch tree in LaTeX just like in the picture below. I need some help with the code. I don't know how to make it.

Answer 1

This needs some adjustment and polishing (e.g. I'm not clear what the algorithm for the labels is so mine is likely not quite right and some labels are likely explicitly specified without need) but if you use forest you can have a lot of the labelling handled automatically for you:

\documentclass[tikz,border=5pt]{standalone}
\usepackage{forest}
\begin{document}
  \tikzset{
    every label/.append style={font=\scriptsize},
    my edge labels/.style={font=\scriptsize},
    dominant/.append style={label=below:$dominant$},
  }
  \begin{forest}
    for tree={
      circle,
      draw,
      minimum width=2.5em,
      l sep+=1.5em,
      s sep+=1em,
      anchor=center,
      edge path={
        \noexpand\path[\forestoption{edge}](!u.parent anchor)--(.child anchor)[my edge labels]\forestoption{edge label};
      },
    },
    delay={
      where n=1{
        edge label/.wrap 2 pgfmath args={
          node[midway, left]{$b_{#1}={#2}$}}{level}{n}
      }{
        edge label/.wrap 2 pgfmath args={
          node[midway, right]{$b_{#1}={#2}$}}{level}{n}
      },
    }
    [0, label={left:$L_2=L_3=3$}
      [1
        [2
          [3
            [4
            ]
            [12, label={below:$L_2=4$}
            ]
          ]
          [,phantom]
        ]
        [13, s sep+=1.5em, label={right:$L_3=3$}
          [{\phantom{a}}, dominant
          ]
          [14, label={below:$L_3=4$}
          ]
          [15, label={right:$L_3=3$}
            [, dominant
            ]
            [16, label={right:$L_3=3$}
            ]
          ]
        ]
      ]
    ]
  \end{forest}
\end{document}

EDIT

Tidied up the alignment etc. a bit, and used styles to ensure some consistency in formatting of labels etc.

Answer 2

You can use the tikz package and generate one as follows:

\documentclass{article}

\usepackage{tikz}

\begin{document}

\begin{tikzpicture}
\tikzstyle{level 1}=[sibling distance=30mm]
\tikzstyle{level 2}=[sibling distance=10mm]
\tikzstyle{level 3}=[sibling distance=5mm]
\tikzstyle{level 4}=[sibling distance=5mm]
\node{A}
    child
    {
        node{B}
            child
            {
                node{D}
                    child{node{H}}
                    child{node{I}}
            }
            child
            {
                node{E}
                    child{node{J}}
                    child{node{K}}
            }
    }
    child
    {
        node{C}
            child
            {
                node{F}
                    child{node{L}}
                    child{node{M}}
            }            
            child
            {
                node{G}
                    child{node{N}}
                    child{node{O}}
            }
    };
\end{tikzpicture}

\end{document}

You must read the tikz documentation in order to customize the tree according to your needs.

Also you can use the qtree package like this:

\documentclass{article}

\usepackage{qtree}

\begin{document}


\Tree [.S [.NP LaTeX ] [.VP [.V is ] [.NP fun ] ] ]


\end{document}

Again qtree documentation will help you.

Source Wikipedia